银杏细胞提取物的药理作用研究

采用化学比色法,研究了银杏细胞提取物在体外对人LDL的氧化抑制和对DPPH自由基清除的作用.对LDL氧化反应潜伏期大小依次为:EGBC>BHT>>Control,EGBC、BHT对DPPH自由基的氧化抑制率分别为53.8%和42.7%.体内实验表明:EGBC可降低肝中MDA含量,提高肝中SOD和GSH-Px的活力.肿瘤对照组小鼠的胸腺明显缩小,胸腺平均湿重、红细胞Hb平均含量、红细胞及胸腺与肝中SOD活性均明显低于正常对照组.而EGBC组小鼠胸腺平均湿重、红细胞Hb平均含量、红细胞及胸腺与肝中SOD活性明显高于肿瘤对照组,Hb的含量接近正常对照组,SOD活性比正常对照组要高.结论:在实验条件下,EGBC对人LDL的氧化具有抑制作用,对DPPH自由基具有一定的清除作用,对乙醇诱导的肝损伤具有保护作用,对荷S180小鼠的肿瘤生长有抑制作用.     

黄酮类化合物保护低密度脂蛋白氧化作用和减少动脉粥样硬化作用

食用含黄酮类物质食物将导致它们在血浆和组织中出现,摄入量和心血管的疾病成反比关系可能是与黄酮类减少了低密度脂蛋白氧化作用。黄酮类对动脉低密度脂蛋白细胞间接氧化作用可通过对他们在脂蛋白动脉的细胞累积来测定,如巨噬细胞。黄酮类可清除反应的氧、氮种类,螯合金属离子和节制低密度脂蛋白联合抗氧化作用,减少低密度脂蛋白氧化作用。通过抑制细胞氧合酶(如烟酰胺、腺嘌呤、二核甙酸、磷酸盐,减少氧化酶的形成)或通过启动细胞抗氧化剂(如谷胱甘肽系统)也能减少巨噬细胞氧化压力。 因此,黄酮类植物是有效的天然的抗氧化剂,既能保护反抗动脉细胞和脂蛋白类脂过氧化作用,又能有效的减少动脉粥样硬化的形成。     

Evaluation of antioxidant properties of pomegranate peel extract in comparison with pomegranate pulp extract

Pomegranate is an important source of bioactive compounds and has been used for folk medicine for many centuries. Pomegranate juice has been demonstrated to be high in antioxidant activity and is effective in the prevention of atherosclerosis. In a previous study, we found that pomegranate peel had the highest antioxidant activity among the peel, pulp and seed fractions of 28 kinds of fruits commonly consumed in China as determined by FRAP (ferric reducing antioxidant power) assay. In this study, we extracted antioxidants from pomegranate peel, using a mixture of ethanol, methanol and acetone, and the antioxidant properties of the extract were further investigated as compared with the pulp extract. The contents of total phenolics, flavonoids, proathocyanidins and ascorbic acid were also measured. The results showed that pomegranate peel extract had markedly higher antioxidant capacity than the pulp extract in scavenging or preventive capacity against superoxide anion, hydroxyl and peroxyl radicals as well as inhibiting CuSO₄-induced LDL oxidation. The contents of total phenolics, flavonoids and proathocyanidins were also higher in peel extract than in pulp extract. The large amount of phenolics contained in peel extract may cause its strong antioxidant ability. We concluded that pomegranate peel extract appeared to have more potential as a health supplement rich in natural antioxidants than the pulp extract and merits further intensive study.     

叶黄素对早期动脉粥样硬化的保护作用及其机制

叶黄素是类胡萝卜素之一,因其具有独特的生物活性而备受关注。它含有羟基和多个共轭不饱和双键结构,具有抗氧化作用,能够抑制LDL过氧化损伤和抑制血管内皮细胞黏附分子的过度表达,对早期动脉粥样硬化可能具有保护作用。重点介绍了叶黄素对早期动脉粥样硬化的保护作用及其机制的研究进展。     

Hypercholesterolemia and inflammation in atherogenesis: two sides of the same coin

An abundance of experimental, clinical, and epidemiologic data capped by stunning interventional results with the statins has established hypercholesterolemia as a major causative factor in atherogenesis. In familial hypercholesterolemia and in animal models it is a sufficient cause. Some degree of hypercholesterolemia, perhaps 30–50 mg/dL, may even be a necessary cause. It is equally clear that from the very beginning atherogenesis has a strong inflammatory component, i. e., it is characterized by penetration of monocytes and of T‐cells into the developing lesion. These cells, through the secretion of cytokines and growth factors, through immune responses, and through complex cross‐talk with elements of the artery wall modulate the growth of the lesion and affect its stability. But inflammation has to occur in response to something. What is that something? What is the “injury” in “response‐to‐injury”? The case will be made that oxidized lipids in oxidized LDL or generated in response to prooxidative changes in the cells of the artery wall should be considered a plausible candidate. There is no need to consider hypercholesterolemia and inflammation as alternative hypotheses. Both are very much involved. Optimal intervention and prevention will probably require attention to both.     

Isolation of ellagic acid from the aqueous extract of the roots of Decalepis hamiltonii: Antioxidant activity and cytoprotective effect

Roots of Decalepis hamiltonii are consumed as pickles and as a beverage and are believed to possess health-promoting properties. Roots of D. hamiltonii exhibit antioxidant properties. We have isolated an antioxidant compound from the aqueous extract of the roots of D. hamiltonii and identified it as ellagic acid (EA), based on NMR and MS. EA exhibited free radical-scavenging activity, inhibited LDL oxidation and showed cytoprotective effect against xenobiotic-induced oxidative stress in Ehrlich Ascites tumor cells. EA is a new addition to the list of antioxidant compounds in the roots of D. hamiltonii.     

番茄红素、花色素的抑制Ox-LDL效果研究

一项流行病学调查结果显示常饮葡萄酒可能产生预防心血管疾病的作用。葡萄中含有丰富的黄酮类和花色苷类成分，这些物质成分也是水果和蔬菜中大量含有的物质成分，除此而外，果、蔬中的花色素类、黄酮类、多酚类、类胡萝卜素类以及维生素C等主要含量成分是否具有预防心血管疾病的效果，通过对比实验方法说明，属于类胡萝卜素类的番茄红素、花色苷、多酚类以及维生素C也有类似葡萄提取物的抑制LDL氧化效果。因此，多食用水果和蔬菜可能有预防心血管疾病的作用和效果。     

Synergistic effects of phenolics and carotenoids on human low-density lipoprotein oxidation

Low-density lipoprotein oxidation is believed to play an important role in the development of atherosclerosis and therefore a high resistance of LDL against oxidation may prevent atherogenesis and accompanying disorders. Several secondary plant metabolites have been tested for their ability to prevent oxidation of LDL and many phenolics as well as carotenoids have been shown to enhance LDL oxidation resistance. We showed that the quercetingylcoside rutin is able to inhibit copper-induced formation of conjugated dienes and loss of tryptophan fluorescence in LDL. However, enrichment of LDL with the carotenoids lutein or lycopene did not result in an alleviation of LDL oxidation. Since there is an agreement that not one antioxidant alone can lead to health benefits but the combination, as found for example in fruits and vegetables, is the active principle, we tested whether the combination of a phenolic compound (i. e. rutin) and carotenoids (i.e. lutein or lycopene) leads to synergistic effects. Both combinations were shown to exert supra-additive protection of LDL towards oxidation, which is most likely due to different allocation of the antioxidants in the LDL-particle and to different mechanisms of antioxidant action.     

Comparative studies on the antioxidant activities of nine common food legumes against copper-induced human low-density lipoprotein oxidation in vitro

ABSTRACT:  Epidemiological studies demonstrated that the consumption of dietary antioxidant was associated with the prevention of atherosclerosis. The aim of this study was to investigate the antioxidant activities of the hydrophilic extracts from 9 selected legumes based on copper-induced human LDL oxidation model in vitro . The antioxidant activities were assessed on the basis of the formation of conjugated dienes (lag time of oxidation) and thiobarbituric acid reactive substances (TBARS) as the early and later stage markers of LDL oxidation. The results showed that the extracts of black beans ( Phaseolus vulgaris L.), lentils ( Lens culinaris ), black soybeans ( Glycine max ), and red kidney beans ( Phaseolus vulgaris L.) had significant ( P < 0.05) longer LDL oxidation lag times (128.8, 124.2, 107.7, and 111.1 min, respectively) than the LDL control group (94.9 min). No significant lag-time lengthening was observed in other tested legume extracts. On the other hand, black beans, lentils, black soybeans, red kidney beans, and pinto beans exhibited higher antioxidant capacities (Trolox equivalents) than yellow peas, green peas, chickpea, and yellow soybeans in both LDL-conjugated dienes assay and LDL-TBARS assay. Meanwhile, the antioxidant activities of these legumes against LDL-lipid peroxidation in the above assays were found to correlate very significantly ( P < 0.01) with their phenolic substances, and DPPH radical scavenging activity and ORAC (oxygen radical absorbance capacity). These results suggest that consuming black beans, lentils, black soybeans, and red kidney beans may have potential in preventing the development of atherosclerosis from the perspective of inhibiting LDL oxidation.     

Differential partitioning of antioxidants, including hydroxytyrosol, in human plasma and LDL: Implications for their antioxidant activity invivo

Invivo studies of LDL oxidation following consumption of natural phenolic compounds have yielded mixed results. It is reported that the amphiphilic hydroxytyrosol, after addition to human plasma, does not accumulate in LDL but protects plasma lipids, which are extracted together with hydroxytyrosol, from chemically-induced oxidation. Thus, a novel methodology was proposed, which does not rely on LDL separation and subsequent oxidation but is based on the oxidation of total lipids - simultaneously extracted from plasma with antioxidants - to evaluate the effects of micronutrients that do not partition into LDL, after invivo supplementation.     

Effects of Different Simple Triglycerides on Cell Fatty Acid Compositions,Proliferation‐Related Protein,and Gene Expressions Induced by Oxidized‐LDL in HUVSMCs

The proliferating effects of 3 different simple triglycerides (tristearin, triolein, and trilinolein) on the human umbilical vein smooth muscle cells (HUVSMCs) induced by oxidized‐LDL (ox‐LDL) were investigated in this study. The protein and mRNA gene expressions of proliferating cell nuclear antigen (PCNA), smooth muscle‐α‐actin (SM‐α‐actin), and monocyte chemoattractant protein‐1 (MCP‐1) in HUVSMCs were measured by Western blotting and real‐time quantitative polymerase chain reaction (PCR). It was shown that in tristearin (SSS) treated HUVSMCs, the saturated fatty acid content was increased, and the compositions of polyunsaturated fatty acid (PUFA) and monounsaturated fatty acid were decreased significantly. On the other hand, triolein (OOO) and trilinolein (LLL) significantly increased the levels of some typical PUFA such as arachidonic acid, eicosapentaenoic acid, and docosahexaenoic acid. Moreover, LLL and OOO could upregulate the protein and mRNA expressions of PCNA, MCP‐1 as well as downregulate the expression of SM‐α‐actin. The results also showed that, SSS had significant promotion effects on the proliferation of HUVSMCs induced by ox‐LDL. Although both LLL and OOO could inhibit the proliferation of HUVSMCs induced by ox‐LDL, and might have certain inhibition of the atherosclerotic process.     

The Roles of Garlic on the Lipid Parameters: A Systematic Review of the Literature

Garlic has long been the focus of experimental and clinical attentions due to its promising lipid-lowering effects. Numerous animal studies as well as in vitro ones have demonstrated the hypolipidemic effects of garlic, while clinical trials are highly inconsistent. Based on some double-blind, randomized, placebo-controlled clinical trials which denied the hypolipidemic effects of garlic, some meta-analysis concluded that garlic did not possess beneficial effects for hyperlipidemia. However, we should not ignore the abundant supporting data in the literature. It should be noted that the doses of garlic used in clinical trials were usually far lower than those used in animal studies, which might cover its potential effects. The type of the garlic products may be another important factor responsible for the conflicting outcomes, as different garlic products are composed of different organosulfur compounds. In addition, the biological availability of garlic products is of importance, which was omitted in many studies. Moreover, some studies indicated that different people might have a different response to garlic, and thus garlic may be more beneficial for some specific groups. Collectively, it may be inappropriate to draw a conclusion that garlic does not benefit for hyperlipidemia. Future studies with larger samples are needed to further clarify the effects of garlic used at higher but non-toxic doses on specific groups.     

Lycopene and Its Antioxidant Role in the Prevention of Cardiovascular Diseases—A Critical Review

The present review is based mainly on papers published between 2000 and 2011 and gives information about the properties of the carotenoid lycopene in chemical and biological systems and its possible role in preventing cardiovascular diseases (CVD). The main aim of this report is to highlight its role as an antioxidant, also reported are bioactive properties that may influence the development of foam cells and protection against endothelial cell damage. The paper will also examine recent observations that lycopene may improve blood flow and reduce inflammatory responses. Lycopene possesses antioxidant properties in vitro, and some epidemiological studies have reported protective effects against the progression of CVD. The oxidation of human low density lipoproteins (LDL) is a fundamental mechanism in the initiation of atherosclerosis. A beneficial role of lycopene as antioxidant in the prevention of CVD is suggested but the data are still controversial. Lycopene is believed to be the most potent carotenoid antioxidant in vitro. Tissue culture experiments and animal studies support potential cardioprotective effects for lycopene and other carotenoids in the blood. Most studies showed beneficial effects of lycopene to individuals who are antioxidant-deficient like elderly patients, or humans exposed to higher levels of oxidative stress like smokers, diabetics, hemodialysis patients and acute myocardial infarction patients. By defining the right population and combining antioxidant potentials of lycopene with vitamins and other bioactive plant compounds, the beneficial role of lycopene in CVD can be clarified in future studies.     

Fungal siderophores function as protective agents of LDL oxidation and are promising anti-atherosclerotic metabolites in functional food

Iron-mediated oxidation of low-density lipoprotein has been implicated in the pathogenesis of vascular disorders such as atherosclerosis. The present investigations were performed to test whether hydrophobic fungal siderophores - hexadentate trihydroxamates desferricoprogen, desferrichrome, desferrirubin, and desferrichrysin - might suppress heme-catalyzed LDL oxidation and the toxic effects of heme-treated LDL on vascular endothelium. Indeed, two of these - desferricoprogen and desferrichrome - markedly increased the resistance of LDL to heme-catalyzed oxidation. In similar dose-response fashion, these siderophores also inhibited the generation of LDL products cytotoxic to human vascular endothelium. When iron-free fungal siderophores were added to LDL/heme oxidation reactions, the product failed to induce heme oxygenase-1, a surrogate marker for the noncytocidal effects of oxidized LDL (not in the case of desferrichrysin). Desferricoprogen also hindered the iron-mediated peroxidation of lipids from human atherosclerotic soft plaques in vitro, and was taken up in the gastrointestinal tract of rat. The absorbed siderophore was accumulated in the liver and was secreted in its iron-complexed form in the feces and urine. The consumption of mold-ripened food products such as aged cheeses and the introduction of functional foods and food additives rich in fungal iron chelators in diets may lower the risk of cardiovascular diseases.     

Antioxidant effect of oregano (Lippia berlandieri v. Shauer) essential oil and mother liquors

The conventional steam distillation process for oregano (Lippia berlandieri v. Shauer) essential oil extraction produces large volumes of mother liquor. This residual liquid represents a potential value because the soluble antioxidants it contains. Essential oil and ethyl acetate mother liquor extracts (MLEs) were evaluated for antioxidant activity. Total phenolic content and antioxidant activities by the 2-2′-diphenyl-1-picrylhydrazyl (DPPH) method, by the deoxyribose degradation assay, and by oxidation of low density lipoproteins (LDL) with CuSO₄ were evaluated. Oil yield was 4.34%. Total phenolic content was 151 ± 2.00 and 150.5 ± 0.98 mg of GAE (gallic acid equivalents)/mL for the essential oil and MLEs, respectively. DPPH assay showed a low radical scavenging activity (RSA) for oregano essential oil. Meanwhile MLEs exhibited no significant RSA at low concentrations, but at higher concentrations (100 μg/mL), it was superior to those exhibited by the controls ascorbic acid and butylated hydroxytoluene (BHT). Deoxy-d-ribose assay results for both essential oil and MLEs showed a good hydroxyl radical RSA at the concentrations tested. Essential oil and MLEs delayed induction time effectively. Solubility problems, chemical constituents, and their hydrophilic–lipophilic distribution are key factors that explain samples behavior for an eventual use of these natural products.     

A diet rich in Maillard reaction products protects LDL against copper induced oxidation ex vivo, a human intervention trial

Maillard reaction products (MRPs) have antioxidative properties in vitro but the influence of a diet rich in MRPs on oxidative damage in vivo remains unknown.In this study, the influence of thermally processed foods rich in MRPs on copper induced oxidation of human low-density lipoprotein (LDL) in vitro was examined. Moreover, oxidative resistance of LDL (OR) in blood plasma of eight healthy subjects was monitored, who consumed diets poor and rich in MRPs in weekly turn for 3 weeks.Dark beer, bread crust, and roasted coffee led to a statistically significant increased OR in vitro compared to pale beer, bread crumb, and raw coffee. The consumption of a diet rich in MRPS significantly increased plasma OR compared to the diet poor in MRPs by 35.5%.This study indicates that thermally processed foods rich in MRPs inhibit the LDL oxidation in vitro and have the ability to reduce oxidative modification of LDL in vivo.     

“Potential Health Benefits of Lunasin: A Multifaceted Soy‐Derived Bioactive Peptide”

Bioactive peptides are small protein fragments derived from enzymatic hydrolysis of food proteins, fermentation with proteolytic starter cultures, and gastrointestinal digestion. These peptides have positive impacts on a number of physiological functions in living beings. Lunasin, a soy‐derived bioactive peptide, is one of the most promising among them. Lunasin encoded within 2S albumin (GM2S‐1) gene, identified as a novel peptide extracted from soybean seed. It is composed of 43 amino acid residues with a molecular weight of 5.5 kDa. Extensive scientific studies have shown that lunasin possesses inherent antioxidative, anti‐inflammatory, anticancerous properties and could also play a vital role in regulating of cholesterol biosynthesis in the body. Its high bioavailability and heat stable nature allow its potential use as dietary supplement. The present review summarizes some of the potential health and therapeutic benefits of lunasin reported hitherto.